NEW YORK — The years take their toll on Emilia Marty. She has seen friends and lovers die, watched joy and despair come and go. But she is more jaded than most in her old age, and with good reason.

When Marty hears the news that a man has killed himself — and on her account — she basically shrugs. “Lots of people do,” she says.

Leos Janacek’s “The Makropulos Case” takes a story about an opera singer who lives for more than 300 years, and yanks it out of the realm of fantasy and into one of philosophy. At the Metropolitan Opera on Friday, Karita Mattila sang the leading role, a character who is born Elina Makropoulus but later adopts the Marty moniker. Mattila can be a riveting performer, and particularly in the third act, her gifts were well served.

The challenges of the unusual piece were evident and the production sometimes questionable. But on its own merits, the rarity is worth seeing and the cast, overall, commendable.

An inheritance dispute frames the story. As the debt-saddled Albert Gregor anxiously awaits the results of a legal case that drove his father to suicide, Marty arrives, claiming proof that Gregor should prevail over the Baron Prus.

The work plays more like a drama than an opera — text is often set to mimic Czech speech, rather than drawn out so the audience can bask in vocal glories. But each emotion, each bit of subtext is given a thorough rundown in the fraught, mysterious score.

It’s a formidable coordination task for all involved. The rhythmically difficult vocal lines require a conversational feel, but also need to project. And especially for Marty, a symbol of magnetic youthful allure in voice and body, tone quality matters.

Conductor Jirí Belohlávek spurred the Met orchestra on to fits of frenzy and pathos, including lovesick rants for Gregor and a rapturous final monologue for the leading lady.

Marty can credibly be played as coldhearted, sapped of all compassion. Relatives become meaningless when, as she says, she could have thousands of descendents. Here, in Elijah Moshinsky’s revived 1996 production, she is more sympathetic.

Mattila’s inflections and gestures are nuanced throughout. If one could hope for a little more strength occasionally, her voice still has a distinctive appeal. But she sometimes appeared misdirected. For the first two acts, she was often stuck with cheesy vamping. In general, the staging had a tendency to look awkwardly posed or choreographed.

Sets by Anthony Ward added style to the opera’s potentially dull locales with a pixelated projection of the diva’s face, a big Sphinx on which Mattila lounged and a backdrop of multilingual scribblings, a nod to Marty’s love letters and the paper on which she rediscovers her father’s formula for longevity. Costumes by Dona Granata were glamorous enough and flattering.

Matthew Plenk lent Janek a robust, focused sound. Emalie Savoy, a member of the Met’s young artist program in her debut, offered a light-textured but richly colored voice as Kristina.

Bernard Fitch was amusing as Count Hauk-Sendorf, a happy, old, philandering fool who comes closest to answering the show’s questions about pleasure and purpose.

Twitter: @RonniReich

The Makropulos Case
Where: The Metropolitan Opera, Broadway and 66th Street, New York
When: Tonight, May 8 and May 11 at 8:30 p.m., and May 5 at 12:30 p.m.
How much: $25 to $430. Call (212) 362-6000 or visit metopera.org.
Karita Mattila is riveting as Elina Makropulos.